It has previously been proposed to integrate an electric generator structure with the flywheel of an internal combustion engine, typically of the automotive type. This arrangement permits obtaining relatively high output from only segmentally placed stators, since the diameter of the flywheel is considerable; difficulties arise, however, in connection with attaching the electromagnetic structural components of the dynamo electric machine, for example a permanent magnet field and an armature stator package, to the respective housing and flywheel components of the internal combustion (IC) engine, due to the short axial length thereof and the brittleness of many of the electromagnetic structural components. Additionally, the working space to place attaching elements frequently is limited and, especially if repair or replacement of elements is needed, it is difficult to obtain access to the respective components.
High magnetic forces arise in operation. Integrating the generator structure with the flywheel also subjects the respective components to thermal expansion. The thermal expansion of the housing of the flywheel and of the stator elements may differ. It is thus necessary to provide a tight and secure connection between the stator elements, typically the armature electromagnetic structure and the flywheel housing. The rotor element, typically the field and usually a permanent magnet field, likewise places special requirements on the attachment arrangement. Permanent magnetic field elements are quite brittle. When placed at the outer circumference of the flywheel of an IC engine, they are subjected to high centrifugal forces. The structural space for attaching the elements, in axial direction, is limited. Successful placement of the magnetic structural components of a generator has led to difficulties.